Charles Ellicott Commentary Deuteronomy 5:4

"Jehovah spake with you face to face in the mount out of the midst of the fire," — Deuteronomy 5:4 (ASV)

The Lord talked with you face to face. —Yet they saw no manner of similitude (Deuteronomy 4:12), i.e., no visible form: but the very words of God reached their ears. So in Exodus 20:22, You have seen that I have talked with you from heaven.